EDTA as a corrosion inhibitor for Al in 0.5 M HCl: adsorption, thermodynamic and theoretical study

Abstract

<p class="Default"><span lang="EN-US">In this study; EDTA is used in very small amount (10<sup>-10</sup> M) as an inhibitor for the Al corrosion in 0.5 M HCl. Thermodynamic and adsorption parameters are calculated. The result shows that, in this range of concentrations, EDTA is chemisorbed at the Al surface, forming a stable complex with Al and give inhibition efficiency up to 89 %. For more con­centration, unstable complex is formed and acceleration of corrosion occurs. The adsorp­tion fit well to Langmuir, Temkin isotherms and El-awady model. Density functional theory (DFT) is used to study the geometrical optimizations of EDTA. From the obtained optimized structure, The highest occupied molecular orbital (EHOMO), the lowest unoc­cupied molecular orbital (ELUMO and their energy difference (ΔE), the total energy (TE), electronegativity (χ), dipole moment (µ), global hardness (η), global softness (σ), elec­tron affinity (A), ionization potential (I), the fraction of electrons transferred (∆N) and were determined using B3LYP/6-31G(d,p) basis set.</span></p>

Mannich Base as an Efficient Corrosion Inhibitor of AA6061 in 0.5 M HCl: Electrochemical, Surface Morphological and Theoretical Investigations

“…However, the LUMO's density distributions were mainly around the benzene ring. As reported earlier, inhibitor with higher E HOMO values shows a greater tendency to donate electrons to the metal, whereas a higher E LUMO value accepts electrons from the metal [49]. MBS's keto form showed a higher E HOMO and lower E LUMO value (Table 7) than the enol form.…”

Corrosion Resistance of Aluminum against Acid Activation: Impact of Benzothiazole-Substituted Gallium Phthalocyanine

“…These diffraction peaks are indexed as orthorhombic phase of boehmite AlOOH (JCPDS number 00-021-1307) for 2θ = 39.3 and 65.8°, as cubic γ-Al 2 O 3 (JCPDS number 00-001-1303) for 2θ = 45.5° and as face centered cubic aluminum (JCPDS number 004-0787) for 2θ = 65.8 and 78.8°. On comparison with diffraction peaks of metallic aluminum, peaks at 2θ = 39.3, 45.5, 65.8, 78.8 and 83.1° match well (JCPDS number 89-4037) [63,64,65,66,67].…”

From initial treatment design to final disposal of chelating agents: a review of corrosion and degradation mechanisms

“…It has been shown to inhibit corrosion on mild steel and aluminum in 0.5 M HCl through adsorption of the EDTA molecule on the metal surface. 81,82 Both authors demonstrate that EDTA was able to both inhibit corrosion by acting as a mixed inhibitor and prevent pitting on the metal surface immersed in the acid solution. Even in 1 M of HCl, EDTA was still able to perform comparatively well against thiourea, a conventional corrosion inhibitor at room temperature.…”